Apparatus for winding electrically conducting metal strips



J. GAUDIN APPARATUS FOR WINDING ELECTRICALLY CONDUCTING METAL STRIPS Filed June 23, 1966 2 Sheets-Sheet l INVENTOR fiwf/lww KARI.- fl'ATI/ ATTORNEY J. GAUDIN April 30, 1968 APPARATUS FOR WINDING ELECTRICALLY CONDUCTING METAL STRIPS 2 Sheets-Sheet 2 Filed June 23, 1966 Fla. 2:.

\ T T fhfiffir 4L MT fig Tfifififia J 1L w 1 3% I -iL INVENTOR filmy/00w KARL RAT ATTORNEY nited States Patent 3,380,686 APPARATUS FOR WINDING ELECTRICALLY CONDUCTING METAL STRIPS Jean Gaudin, Montigny-les-Cormeilles, France, assignor to Societe de Constructions Mecaniqucs tl'e Creil, a corporation of France Filed June 23, 1966, Ser. No. 559,834 Claims priority, application France, June 25, 1965,

5 Claims. iii. 242-751 ABSTRACT OF THE DISCLOSURE In winding strips of electrically conducting material upon an arbor with the strips being exposed, prior to winding, to a magnetic braking field, to maintain a substantially constant winding tension, difficulties have been experienced where the strips are previously slit into a plurality of juxtaposed partial strips to be simultaneously wound upon a common arbor. Due to variations of the tensions of the partial strips resulting from the slitting operations or other causes, the winding tensions of the strips vary accordingly. The difi'iculty is overcome by the provision of spaced rows of discrete braking magnets disposed across the total width of the partial strips with the magnets of each row being mutually spaced and adjacent rows being displaced laterally of the strips and relative to each other, to cause each of the partial strips to be subject to eddy current braking by the field of at least one of said magnets. The resultant individual braking of v the partial strips in turn results in substantially uniform winding tensions of all the strips being wound upon the common arbor.

The present invention relates to the winding of metallic strips and the like elongated members upon a receiving arbor or mandrel and has for its main object the provision of an improved method and apparatus to control the winding tension of the strips, such as to keep the tension at a constant value throughout the winding or reeling operation.

In metallurgical plants, it is customary to slit the webs of great width by mounting the reels on the arbor of an unreeling machine, the reels being unwound and the strips or webs slit or cut in the longitudinal direction by means of a shearing mechanism employing circular blades, whereupon the parted partial strips being wound or reeled again on a receiving arbor.

In practice, it is customary in winding operations of this type, for equalizing purposes, to provide a catenary sag between the winding and shearing mechanism and to maintain this sag, such as by operating the shearing mechanism in synchronism with the winding or reeling arbor.

In the carrying out of a combined slitting and reeling operation of this type, it is observed that the height of the sag is not constant for each of the partial strips cut from an original wider strip or web. After rolling, certain webs have so-called long edges, which after slitting may result in lesser tension in the outer or extreme strips. Other webs exhibit variations in thickness or other characteristics which cause, at the time of winding, variations in the diameter of the receiving reels and, as a result, differences in the linear velocities of the strips. This, in turn, will result in non-uniform winding tensions and irregularly wound reels, as will be understood.

Among the more specific objects of the present invention is, therefore, the provision of a method of and means for the control of the winding tension in winding or reeling apparatus of the referred to type which will ensure reeling under controlled or substantially constant tension of each of the partial strips in conjunction with a comice bined slitting and winding operation; which will make it possible to control the winding tension of the strips or webs separately and independently; and which is devoid of any direct mechanical action on the strips, to thereby obviate the risk of damaging the surfaces of the strips or the like elongated members being wound.

The invention, both as to the foregoing and ancillary objects, as well as novel objects thereof, will be better understood from the following detailed description, taken inconjunction with the accompanying drawings forming part of this specification and in which:

'FIG. 1 is a schematic perspective view showing, by way of example, a slitting line or apparatus including a magnetic braking or deceleration device according to the invention;

HG. 2 is an enlarged schematic end view of the braking device of FIG. 1;

FIG. 3 is a horizontal sectional view taken on line IIIIII of FIG. 2; and

FIG. 4, being a view similar to FIG. 1, shows a modified slitting and winding apparatus embodying the principles of the invention.

Like reference numbers denote like parts in the different views of the drawings.

With the foregoing objects in view and in accordance with one aspect of the invention, the improved method of controlling the winding of a web or strip of electrically conducting material onto a reel or the like, comprises essentially the step of passing the web or strip through a magnetic field of adequate strength before winding it onto the reel, to generate, at a given winding speed, eddy currents in the web or strip which, in a known manner react with the magnetic field to brake or decelerate the strip such as to maintain a substantially uniform tightness of winding on the reel or reels. In other words, the conversion of part of the kinetic energy of the strip or strips into electrical energy in the form of eddy currents results in the deceleration of the strips and corresponding increase of the winding tension.

From another aspect, the invention involves the provision of apparatus for performing the said method comprising at least one permanent magnet or electromagnet having a pair of poles forming a gap through which is passed the strip or the like elongated member or members to be reeled or wound.

A device of this nature, being advantageously positioned at the trailing end of the sag provided ahead of the winding reel, makes it possible to exert a holding back action on the web or each of a number of strips parted therefrom without involving any direct mechanical action on or contact with the strips, thus obviating the risk of tearing or damaging the surfaces of the webs or strips being wound.

In the case of non-magnetic metals, the webs may simply be guided by rollers situated at the ingress and egress of the device. In the case of magnetic metals, the poles of the braking magnet are advantageously covered by an insulating layer of small thickness, in such a manner as to prevent adherence or sticking of the webs or strips to the poles by direct magnetic attraction.

According to a preferred construction, suitable control means are provided to vary the width of the magnetic gap through which the strips or webs are passed, to adjust the strength of the magnetic field and/ or to facilitate passage of the webs or strips through the gap, or to adapt the device for use with strips of varying gauge thickness.

Besides, the value of the braking force or deceleration applied to the strips, which varies as a function of the square of the magnetic field for a given winding speed, may be controlled either by varying the gap between the magnet poles by any suitable means, in the case of permanent magnets, or by the variation of the electric exciting or energizing current or currents, when an electromagnet or magnets are employed.

The invention may be advantageously applied to operations which include one or more rewinding stages and in which several strips of electrically conducting material are handled or processed simultaneously, examples being well-known pickling, sealing or painting lines or the like operations.

The invention is also applicable to the rewinding of single strips or webs of any width, or the like elongated members, such as wires, coming either direct from a rolling mill, or from any other processing device, for example benches for tinning or edge rubbing, truing, pickling or painting lines, to name a few examples only. The invention, in all these and similar processing operations, enables in a most simple manner evenly wound reels of controllable tightness and substantial uniformity to be obtained.

Besides, the method and apparatus of the invention is applicable to metal strips, both magnetic and non-magnetic, as well as to any other electrically conducting materials. It is of particularly useful application where strips of weak or fragile metals or other conducting materials, whose surfaces should not come into direct or frictional contact with any mechanical parts or components, are to be wound or reeled. Other applications and uses, as well as advantages of the invention will become apparent as the description proceeds in reference to the drawings.

Referring more particularly to FIG. 1, the feed reel carrying the relatively wide web 11 is shown at 10, web 11 being slit, in the example illustrated, in the circular shearing mechanism 12, to form three fractional or partial webs or strips 13, 14 and 15 which are rewound as separate reels on a receiving arbor or mandrel 16. The sagging portions of the strips referred to hereinabove are shown at 17 and, in order to maintain this sag, the shearing mechanism 12 is advantageously operated in synchronism with the winding arbor 16 by any suitable means, as indicated by the dot-dash line 18 in the drawing.

According to the invention, the runpast of the strips, or portions thereof near the trailing edge of the sag 17, are braked without mechanical friction in magnetic deceleration device 20, in such a manner that the strips 13, 14, 15, passing between poles N and S of the device, are each wound under substantially constant tension on the receiving arbor 16, thus ensuring that reels are obtained of uniform tightness, irrespective of any existing irregularities of the partial strips of webs. In other words, the braking magnet 20, being disposed at the trailing end of the sag 17, has its pole faces disposed adjoining and preferably parallel to the opposite sides of the web 11, or partial strips 13, 14, 15, respectively.

The magnetic deceleration device 20, in the example more clearly shown in FIGS. 2 and 3, is constituted essentially by a frame 21 forming a closed magnetic circuit and being of any appropriate design, for example of laminated construction or sheets of high-permeability material. This frame carries a number of permanent magnets or electromagnets, which also may be of any appropriate construction and whose poles are denoted by the numeral 22 in the drawing. The poles, in the case of a multiple strip winding arrangement as shown by the drawing are preferably arranged in transverse and staggered rows, or offset, as more clearly shown in FIG. 3, in such a manner that the partial webs or strips 13, 14, 15, etc. passing through the gaps of the magnets, are traversed by the magnetic field of at least one of the magnets, irrespective of the width of the strips or webs.

As has been stated, and according to a further feature of the invention involving the use of permanent magnets, the gaps of the magnets may be controlled either in unison, such as by adjustment of the common frame portion or yoke 21a as indicated by the arrows a in FIG. 2, or separately by individual adjustment of the poles, to cause a selective variation of the deceleration action to be exerted on each of the strips 13, 14, 15. In the case of electromagnets, the energizing current through the separate exciting windings 22a may be controlled by any suitable means to achieve the same effect or result. Variation of the gap width, such as by adjustment of the yoke 21a, also enables the device to be adapted for use with webs or strips of ditferent thickness, or to afford easy engagement or passage of the strips or the like elongated members through the magnetic gaps or braking fields.

It is evident that in the application of the invention to the rewinding of single webs or strips, the device may comprise simply one permanent magnet or an electromagnet, but remaining unchanged otherwise.

In order to facilitate engagement or entry of the strips into the magnetic gaps at the beginning of a winding operation, or following the slitting action, the poles of the magnets may be spread apart as desired, or else the magnetic deceleration device 20 may be split into two parts arranged for separation along a plane corresponding to the gap or gaps.

Any appropriate mechanical or electrical means may be employed which allows of the opening of the magnets, or adjustment of their gap and in turn of the variation of the magnetic field within the gap or gaps, as will readily suggest themselves to those skilled in the art.

If desired, the tension of the strips established according to the invention may be augmented by employing one or a set of braking rollers, such as shown at 23, 24, 25 in FIG. 4 and situated between the magnetic deceleration device 20 and the winding arbor 16.

As will be understood, the magnetic braking field within the gap or gaps between the poles N and S should be of sufficient strength, by the proper design and adjustment of the magnets 22, to result in the generation of eddy currents'of adequate intensity in the strips or webs, or the like elongated members in passing through the magnetic field at a given winding speed, to produce a braking or deceleration effect sufficient to ensure a desired winding tightness, in the manner understood from the foregoing.

While a plurality of magnet elements has been shown in conjunction with the reeling of a number of juxtaposed strips or webs, the same mechanism may be used for the deceleration and winding of a single web of corresponding greater width for reasons of mechanical, electrical, etc. nature.

In the foregoing the invention has been described in reference to a specific illustrative device. It will be evident, however, that variations and modifications, as well as the substitution of equivalent parts for those shown herein for illustration, may be made without departing from the broader scope and spirit of the invention as set forth in the appended claims. The specification and drawings are accordingly to be regarded in an illustrative rather than in a restrictive sense.

I claim:

1. In apparatus for the simultaneous winding of a plurality of juxtaposed strips of electrically conducting material including a rotating winding arbor with means for winding thereon said strips at a predetermined winding speed, the provision of magnetic braking means ahead of said arbor, to maintain substantially constant winding tensions of said strips comprising a plurality of spaced rows of magnetic elements disposed across the total width of the strips with their pole faces close to but spaced from the strips, the elements of each of said rows having a mutual spacing distance and adjacent rows being displaced laterally of the strips and in respect to each other, whereby to cause each of said strips to be subject to eddy current braking by the magnetic field of at least one of said elements.

2. In strip winding apparatus as claimed in claim 1, including means to maintain a sag of said strips immediately ahead of said braking means.

3. In strip winding apparatus as claimed in claim 1, said strips arranged to pass through gaps of said magnetic elements, and means for varying the strength of the magnetic fields within said gaps.

4. In strip slitting and winding apparatus including a roll of electrically conducting strip material and a plurality of juxtaposed slitting devices, to subdivide the strip unwound from said roll into a plurality of partial strips, and a rotating arbor with means for winding thereon said partial strips at a predetermined winding speed, the provision of magnetic braking means interposed between said devices and said arbor, to maintain substantially constant winding tensions of said strips, said braking means comprising a plurality of spaced rows of magnetic element disposed across the total Width of said strips with their pole faces close to but spaced from said strips, the elements of each of said rows being displaced laterally of the strips and in respect to each other, whereby to cause each of said strips to be subject to eddy current braking by the magnetic field of at least one of said elements.

5. In strip slitting and winding apparatus as claimed in claim 4, said slitting means consisting of a row of rotary cutters, and means to synchronize said cutters with said arbor, to maintain a predetermined sag of the partial strips immediately ahead of said braking means.

References Cited STANLEY N. GILREATH, Primary Examiner.

FRANK I. COHEN, Examiner.

N. L. MINTZ, Assistant Examiner. 

